机器学习实战:使用Scikit-Learn与TensorFlow

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"《Hands-On Machine Learning with Scikit-Learn and TensorFlow》由Aurélien Géron撰写,是一本深入探讨机器学习概念、工具和技术,用于构建智能系统的实践指南。本书涵盖了Scikit-Learn和TensorFlow两个强大的机器学习库,旨在帮助读者掌握实际的机器学习技能。" 在这本书中,作者Aurélien Géron首先介绍了机器学习的基础知识,包括监督学习、无监督学习和强化学习的基本概念。他详细解释了如何利用Scikit-Learn库进行数据预处理、特征工程、模型选择和评估。Scikit-Learn是一个在Python中广泛使用的机器学习库,它提供了多种算法,如线性回归、逻辑回归、支持向量机、决策树、随机森林和集成方法等。 书中进一步深入到深度学习领域,介绍了TensorFlow这个开源的计算框架。TensorFlow是Google Brain团队开发的,主要用于构建和训练复杂的神经网络模型。读者将学习如何构建卷积神经网络(CNN)进行图像识别,使用循环神经网络(RNN)处理序列数据,如文本和时间序列预测,以及如何应用强化学习来解决决策问题。 在数据预处理部分,作者讨论了缺失值处理、异常值检测、特征缩放、归一化等技术,这些都是确保模型性能的关键步骤。他还讲述了特征选择和降维方法,如主成分分析(PCA),以减少模型复杂性和提高预测效率。 模型评估与调优是书中的重要部分,Géron详细讲解了交叉验证、网格搜索、随机搜索等策略,用于找到最佳的超参数组合。此外,书中还介绍了正则化和集成方法(如随机森林和梯度提升)来防止过拟合和提高模型的一般化能力。 书中还包括了对机器学习模型的可视化,如使用matplotlib和seaborn库创建数据可视化图表,以及使用TensorBoard来监控和理解神经网络的训练过程。此外,作者还讨论了模型的保存和加载,以便在生产环境中部署和使用。 在深度学习章节,读者将了解卷积层、池化层、全连接层和激活函数的工作原理,以及如何使用优化器(如Adam)和损失函数(如交叉熵)来训练模型。书中还介绍了自然语言处理(NLP)的基本概念,如词嵌入和LSTM模型在文本分类和序列标注任务中的应用。 最后,Géron探讨了一些高级主题,如生成对抗网络(GANs)和变分自编码器(VAEs),这些是目前机器学习研究的热点。 《Hands-On Machine Learning with Scikit-Learn and TensorFlow》是一本全面而实用的教程,适合对机器学习感兴趣,希望掌握Scikit-Learn和TensorFlow的初学者和进阶者。通过这本书,读者不仅能学习到理论知识,还能通过实际项目来提升自己的技能,从而在实际工作中构建智能系统。
2017-12-23 上传
When most people hear “Machine Learning,” they picture a robot: a dependable butler or a deadly Terminator depending on who you ask. But Machine Learning is not just a futuristic fantasy, it’s already here. In fact, it has been around for decades in some specialized applications, such as Optical Character Recognition (OCR). But the first ML application that really became mainstream, improving the lives of hundreds of millions of people, took over the world back in the 1990s: it was the spam filter. Not exactly a self-aware Skynet, but it does technically qualify as Machine Learning (it has actually learned so well that you seldom need to flag an email as spam anymore). It was followed by hundreds of ML applications that now quietly power hundreds of products and features that you use regularly, from better recommendations to voice search. Where does Machine Learning start and where does it end? What exactly does it mean for a machine to learn something? If I download a copy of Wikipedia, has my computer really “learned” something? Is it suddenly smarter? In this chapter we will start by clarifying what Machine Learning is and why you may want to use it. Then, before we set out to explore the Machine Learning continent, we will take a look at the map and learn about the main regions and the most notable landmarks: supervised versus unsupervised learning, online versus batch learning, instance-based versus model-based learning. Then we will look at the workflow of a typical ML project, discuss the main challenges you may face, and cover how to evaluate and fine-tune a Machine Learning system. This chapter introduces a lot of fundamental concepts (and jargon) that every data scientist should know by heart. It will be a high-level overview (the only chapter without much code), all rather simple, but you should make sure everything is crystal-clear to you before continuing to the rest of the book. So grab a coffee and let’s get started!
2017-12-23 上传
When most people hear “Machine Learning,” they picture a robot: a dependable butler or a deadly Terminator depending on who you ask. But Machine Learning is not just a futuristic fantasy, it’s already here. In fact, it has been around for decades in some specialized applications, such as Optical Character Recognition (OCR). But the first ML application that really became mainstream, improving the lives of hundreds of millions of people, took over the world back in the 1990s: it was the spam filter. Not exactly a self-aware Skynet, but it does technically qualify as Machine Learning (it has actually learned so well that you seldom need to flag an email as spam anymore). It was followed by hundreds of ML applications that now quietly power hundreds of products and features that you use regularly, from better recommendations to voice search. Where does Machine Learning start and where does it end? What exactly does it mean for a machine to learn something? If I download a copy of Wikipedia, has my computer really “learned” something? Is it suddenly smarter? In this chapter we will start by clarifying what Machine Learning is and why you may want to use it. Then, before we set out to explore the Machine Learning continent, we will take a look at the map and learn about the main regions and the most notable landmarks: supervised versus unsupervised learning, online versus batch learning, instance-based versus model-based learning. Then we will look at the workflow of a typical ML project, discuss the main challenges you may face, and cover how to evaluate and fine-tune a Machine Learning system. This chapter introduces a lot of fundamental concepts (and jargon) that every data scientist should know by heart. It will be a high-level overview (the only chapter without much code), all rather simple, but you should make sure everything is crystal-clear to you before continuing to the rest of the book. So grab a coffee and let’s get started!